Bunk bed



FIG. 1 is a front perspective view of a bunk bed showing the new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a back elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a right elevation view thereof; and,

FIG. 7 is a left elevation view thereof.

The broken lines in the drawings are for the purpose of illustratingportions of the article that form no part of the claimed design.

CLAIM The ornamental design for a bunk bed, as shown and described.